Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: eleventeen on August 10, 2010, 11:02:14 pm
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I started out building tube gear in the 60's and 70's, and gradually migrated to transistors and chips. It's only recently I've gravitated back to tubes...initiated by my ad in the local paper "we buy tube [crap]" and a nice old guy unloading his entire WW2-era surplus garage on me...with ART-13's and transmitters and 1000 NOS tubes of which maybe 100 are useful and of course there is the unholy quartet of my long-time untouched Fender Deluxe Reverb, Princeton Reverb, Pro Reverb #138, and VibroChamp all left over from when I played more and dealt guitars & amps.
So I am starting to build some tube stuff. And it's a PITA!! With chips & transistors, everything fits on a .100 grid and the parts cost between 3 cents and 75 cents each, mostly 15-25 cents. Almost nothing dissipates heat. You start out at the input and spread out over a piece of $2 perf board. When you're all done, you drill four #6 holes in the corners and screw in four standoffs. Anything bigger than a 1/4 watt resistor and you can figure out a way to throw a tie-wrap around it and it's locked in.
With tubes, you try to save some money using old parts and find they are either so out of spec as to be useless, or corroded so bad you can't solder to them without taking a Milwaukee grinder to them. That is, after you've destroyed components and melted back wire insulation overheating the terminals. Everything requires drilling at least 3/8" holes and mounting screws and nuts and every socket is a $3-5 thing. Oh, and speaking of the terminals, if you don't provide for some spares and need to make some changes, you can change a neatish and well planned layout into a rats nest very quickly. And everything is so big, if you need to add something, there's likely not to be enough room, and you have to be so freekin careful drilling holes for the stuff you left out. Then, you can buy a chassis punch set and have yet another tool.
Bunch o' work, my brothers.
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huh, never thought of it that way...
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I'm just being a whiner. Still, consider the following:
Suppose you had each and every part for a stock BF Twin Reverb on a tabletop, essentially a Heathkit BFTR. Pre-punched chassis, trannies, pots, tubes, turret or rivet board, tube sockets, tube retainers, wire. How long do you think it would take to assemble it?
Board: 2.5 hours including cap board and bias board and pigtails out to tube sockets.
Mount pots and get them straight: .75 hour.
Mount rear switches, fusepost, RCA's: .75 hour
Mount all tube sockets: 1 hour
Trannies: .5 hour
Wire filaments: 1.5 hour
Wire everything else: 2 hours
Checking: 1 hour
With ZERO procurement and everything neatly piled in front of you, (a task that takes at least .5 hour but we'll throw it in for free) that's 10 hours of assy time!
Now notwithstanding that this my be fun or therapeutic, procurement is typically not so much fun, unless you're buying everything form one source w/a credit card.
Parts cost:
Tubes, $100.
Board with components: $200.
Pots: $36 @ $3 ea
Transformers: $150.
Chassis: $50
Sockets, fusepost, switches, jacks: $70.
Freight: $50, assuming most from one or two sources, could be as high as $120.
A lousy Twin Reverb, with no speakers and no cabinet and no chassis straps is worth $800 if your assembly time is worth $10 an hour!
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10 hours in heaven is how see it.
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then to add to it building and finishing a nice cab is another 5-10hrs.
'tis why boutique amps are so expensive
if one does not enjoy the electronic/woodworking/sheet metal working journey, then its best to purchase right off craigslist/ebay/whatever.
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Well, the issue for me is that I can really enjoy "a few hours" of it.
And yes, now I see why boutique amps are $1400.
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Here is an option (for your next build?) - buy a kit from mojo or something like it. No need to bother with chassis punching or tolexing. Its more soldering and wiring together stuff.
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I didn't get into this to save time or money (or even make money). Without wandering off into Nambypambyland, the simple joy of creation is all I need to keep me happy :smiley:
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Feh!
Every guitar I build takes me 50-100 hours, and at least half that time is spent sanding! Try beating that for tedium - bot you don't hear ME complaining!
:wink: :grin:
Gabriel
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It could be worse, what if you didn't know how to do this at all.....
I'd like to be building more, but I'm buried in troubleshooting and repair. Today 2 SS Amps and a Blackface Princeton Reverb came in.... I'm eager to work on the Princeton, not so for the Solid State Carvin and Hartke......
I started in this field by repairing items, I'd rather have tube stuff any day. I'm only recently confident with solid state, mainly because of the lousy low grade printed circuit boards....... I absolutely avoid Surface Mount. My brother-in-Law likes that stuff, but he used to remanufacture computer motherboards for a living.
j.
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Some thing can not be explained or rationally understood ! I just want to help an electron along on a good path, I don't look for my reward in this realm.....HTH :angel
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Tubes = cool.
Solid state = not so cool. :grin:
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LOL, rafe. Nice thoughts. Bigs, I'm not so sure that folks who have to go buy amps do any better or worse. They are worse off when it comes to repairs, that's for sure. As for circuit boards, they can be intimidating or confusing, but I happen to be pretty comfortable with them. Surface-mount = forget it. You don't have the proper soldering/desoldering gear, it's almost impossible to repair thoe without damaging things.
Solid state amps can be tough because when the outputs go out, they almost always suck out the driver transistors. That would be, before your finger leaves the on-off switch. Before the fuse blows. Signal tracing (as used on a scope) is also problematical, because the same waveform seems to appear on just about every component.
IMO the primary reason why I find tubes more tedious is that there really isn't any analog (sorry for the pun!) for tie points and turret boards with chips and transistors. You need to make a junction of three things that don't connect to anything? Just run the leads off to the side, poke 'em thru a hole, make your connection, and run 'em back to where you need them. The mere act of poking a component through the perf board *IS* physically mounting it with mechanical rigidity *AND* gives you a solder point *AND* arranges the parts in neat X-Y fashion all in one action. Soldering is a 2-second touch with a small iron, using wire-wrap wire and making teensy (but perfect) solder joints you can hold it in place with your finger without burning yourself. Unless you're building a specific circuit on a turret board made for same or a turret board with lots of extra positions, with tubes and turret board construction, you're always mentally allocating available turret positions to the parts you need. Then you get to a fat capacitor that takes two spaces and you're goobered. You use 1/4 watt resistors that cost 1/3 cent each, so if you blow one up (or drop it and lose it! LOL) it matters little.
I developed a partial solution to my dilemma, however, since I started this thread: I cut 2" off the long edge of my bench and cut 5" off the overall leg length and screwed some nice heavy swivel (and locking) casters to the bottoms of the legs. Now my bench will fit through the man-door in my garage to the back yard and can be easily rolled outside. So at least for a few hours I can build in the sunshine and get my vitamin D.
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What does this post have to do with amp tools??
Moved!
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I like to think of it as a 4 dimensional jigsaw puzzle with lethal voltages thrown in to add some excitement. :laugh:
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I like to think of it as a 4 dimensional jigsaw puzzle with lethal voltages thrown in to add some excitement.
:laugh: :laugh: :laugh:
Hysterical!
With respect, Tubenit
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1. People like tubes because they sound better. If transistors sounded better, tubes would be relegated to the ash heap of history. Maybe not everyone agrees with this; but enough people do to make a major difference.
2. PCB's are "easier" to work with only after you already have one. In the time it takes to design and fabricate a PCB you could hand wire a circuit point to point. But, if you prefer you can build all your tube amps on PCB's.
3. PCB's tend toward miniaturization which is not fun to work with by hand.
4. Point-to-point is better for modding.
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I have worked on many different types of amps and as someone who does more repair work than scratch building, I definately think that hand wired stuff is easier. Actually "easier" doesn't begin to describe how much "easier" it is.
Another thing...... Although I don't have much experience working on transistor amps, there are many "tube amp" manufacturers that use transistors for various purposes in "all tube" amps. Those amps, although they are "all tube" tend to be more difficult to deal with.
If someone comes in and asks me to modify their fixed bias amp so that the bias voltage is adjustable, generally it is easy to do. Enter a modern high gain "all tube" amp from a couple of different manufacturers that use transistors to drive headphone outputs, or whatever. Next thing you know you've run into a quite complicated situation where you can't just make the bias supply adjustable because the negative voltage also feeds the transistors. So you find yourself scratching your head trying to figure out how to keep the voltage on the transistors constant while making the bias supply adjustable and it just makes for a headache.
I have done it successfully, but if you brought me one of those amps, I assure you that it would cost significantly more for my time and labor than it would for a 1975 Whatever Reverb.
Also, my experience has been that when output transistors die, they super nova and burn the crap out of everything on the event horizon.
One last thing. I can find an old RCA radio/phonograph in a trash heap, cannibalize the parts and build a cool guitar amp using a Dukes of Hazard lunch box (that I picked up in the same trash heap) as the chassis.
Can you do that with transistors?
Dave
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Am I missing something??? It clearly states in the Library under scratch building that it is more costly to scratch build an amp.... :grin: See, I read the Library before posting!!! :angel
My hours spent at the bench snorting solder fumes with the incense burning and some blues playing in the background are some of the most treasured times in my day.
Tedious, naw........
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tell you what..... the sheer satisfaction of playing that one-off strat you built through the HPR amp you built yourself is what it's all about.
and building tube amps is just WAY COOL! they glow in the dark man! :grin:
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Twenty minutes to populate your solid state board and 10 hours to build you tube amp.Then you plug in your SS crap and are rewarded with dry,raspy tone that's thin and lifeless.Then you fire up your tube amp and the sweet tone makes all the hours worth it and then some.
Good trade off if you ask me.
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My hours spent at the bench snorting solder fumes with the incense burning and some blues playing in the background are some of the most treasured times in my day.
Tedious, naw........
Oh Yeah, and when you're done, checked everything, the moment just before you flip the standby for the first time.....heaven!
That's what it's all about, playing your favorite licks for the first time through that amp, that you created not to say the tweaking isn't a blast too. Solid state, what the heck is that :laugh:
al
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Hilarious, Tubenit!
Yes, of course tubes are much better sounding and cooler looking. No argument at all.
Yes, you can cannabalize an old tube record player and make a "champ" or if you're lucky, a Princeton Primitivo. You can do that with transistors. It prolly won't sound too great. The FULL comparison here is, if you get a decent price on a used Champ, you can sell it for what you paid for it, maybe more. Can you sell a naked phono chassis converted to an amp?
I was referrring to building solid state stuff on perf board, not designing and fabricating an etched PC board. Fabbing a PC board is a ton of work and not economical for unit quantities. You'll also have to mechanically support the daylights out of a homebrew PC board, perf or etched, in order to withstand the force of inserting and removing tubes from their sockets.
Sure, building is fun and challenging. Just takes a load of time.
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tell you what..... the sheer satisfaction of playing that one-off strat you built through the HPR amp you built yourself is what it's all about.
+1 on that sentiment. I can now gig/jam with an entirely "self built" rig. That is so very, very satisfying. I don't care how long it takes me.
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eleventeen is just voicing that's he's hooked.
Join the club.
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Can you sell a naked phono chassis converted to an amp?
I don't know. I have never tried and probably never would. That, I think, is irrelevant to my point.
Dave
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eleventeen is just voicing that's he's hooked.
Join the club.
Perhaps this thread is an attempt to leave evidence for our "better halves"... evidence that at least attempts to explain why we can't help ourselves :smiley:
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...
Board: 2.5 hours including cap board and bias board and pigtails out to tube sockets.
Mount pots and get them straight: .75 hour.
Mount rear switches, fusepost, RCA's: .75 hour
Mount all tube sockets: 1 hour
Trannies: .5 hour
Wire filaments: 1.5 hour
Wire everything else: 2 hours
Checking: 1 hour
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Well, that's the trick.
No matter what you build, you will find there is an "unskilled speed" that takes forever, a "skilled speed" that takes much less time, and a "production speed" that can be incredibly fast but often is mechanical and repetitious.
When I made and sold Hoffman boards, I made full use of all of Doug's suggestions for building the boards, and then developed a number of production processes that very much sped up the build/assembly. I didn't even get too far into tooling. But it turns the whole exercise from a hobby to an assembly-line job.
Anyway, speed is possible. But it's just a different animal from solid-state.
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Solder fumes + scrap metal under your nails + burn marks + shocks while listening to D.A.C. makes my day man!!! :wink:
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I started out building tube gear in the 60's and 70's, and gradually migrated to transistors and chips. It's only recently I've gravitated back to tubes...initiated by my ad in the local paper "we buy tube [crap]" and a nice old guy unloading his entire WW2-era surplus garage on me...with ART-13's and transmitters and 1000 NOS tubes of which maybe 100 are useful and of course there is the unholy quartet of my long-time untouched Fender Deluxe Reverb, Princeton Reverb, Pro Reverb #138, and VibroChamp all left over from when I played more and dealt guitars & amps.
So I am starting to build some tube stuff. And it's a PITA!! With chips & transistors, everything fits on a .100 grid and the parts cost between 3 cents and 75 cents each, mostly 15-25 cents. Almost nothing dissipates heat. You start out at the input and spread out over a piece of $2 perf board. When you're all done, you drill four #6 holes in the corners and screw in four standoffs. Anything bigger than a 1/4 watt resistor and you can figure out a way to throw a tie-wrap around it and it's locked in.
With tubes, you try to save some money using old parts and find they are either so out of spec as to be useless, or corroded so bad you can't solder to them without taking a Milwaukee grinder to them. That is, after you've destroyed components and melted back wire insulation overheating the terminals. Everything requires drilling at least 3/8" holes and mounting screws and nuts and every socket is a $3-5 thing. Oh, and speaking of the terminals, if you don't provide for some spares and need to make some changes, you can change a neatish and well planned layout into a rats nest very quickly. And everything is so big, if you need to add something, there's likely not to be enough room, and you have to be so freekin careful drilling holes for the stuff you left out. Then, you can buy a chassis punch set and have yet another tool.
charcoal grilling a porterhouse steak is a tedious pain!! I started out on charcoal and prime rib, porthouse, and NY strip.. but then I spent 40 years eating microwaved flank steak! going back to charcoal grilling and quality steak is a pain!!
first of all,, I'm trying to use my rusty 1960's grill cause I'm a skinflint and I don't wanna peel off a couple bucks if i can use this one...
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Cubans do some pretty inventive cooking with flank stake. They called it "Ropa Vieja". You should try some sometime, its good stuff. But then again, I'm a pork man...... The other white meat.
Glad you chimed in.
Dave
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Wow!!!! There's someone out there who can wire every single wire in a blackfaced twin reverb except the filaments in 2 hours??!! Holy crap! I am a real slowpoke.
You know there is nothing more pleasing then spending hours assembling a classic holy grail amplifier and then playing that sweet thang. However, there is also nothing more frustrating then spending hours assembling a classic holy grail amplifier and then having a problem with it that you spend hours trying to figure out.
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I am 57. I started tearing things apart and rebuilding them when I was 9.
I started tearing things apart when I was 7. Unfortunately for my parents I didn't start putting things back together correctly until I was about 10 :grin:
Remind me never to go to "The Bar" in Midland. :angry:
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I just build stuff for fun or to relax, etc. Once it's built I don't want it. Maybe because I don't play guitar.
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PITA, doesn't even come into view.
Man, you are lucky. I see them all the time around here and it gets very irritating. I mean, come on, I own my goats and by God I should be able to slap the crap out of them anytime I feel the urge. But noooooo, I have to look around and make sure those PITA people are not looking before I can slap the snot out of them.
Dave
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Yes, you can cannabalize an old tube record player and make a "champ" or if you're lucky, a Princeton Primitivo. You can do that with transistors. It prolly won't sound too great. The FULL comparison here is, if you get a decent price on a used Champ, you can sell it for what you paid for it, maybe more. Can you sell a naked phono chassis converted to an amp?
I think I've seen where someone has taken an old PC power supply chassis, converted it to something comparable to a Firefly, and sold it like that, on eBay, without a cab.
I was referrring to building solid state stuff on perf board, not designing and fabricating an etched PC board. Fabbing a PC board is a ton of work and not economical for unit quantities. You'll also have to mechanically support the daylights out of a homebrew PC board, perf or etched, in order to withstand the force of inserting and removing tubes from their sockets.
When I use perfboard for building a tube amp, I mount the sockets to the chassis, and run wires to the board. I don't put the sockets on the board as I've seen a few amps, even el-cheapo bury it in the cabinetry phono players or table-top radios where the heat has damaged the PCB. (Heh, even some of these new amps with all that support fail due to the extra heat.)
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I agree, it can be tedious. I've been trying to build an 18W amp for 7 months now, and I'm about half way there :rolleyes: Another member here, sluckey, did a fantastic job creating the layout for me, but for some reason I've been very slow. I don't want to have someone else do it for me, I definitely want to do it myself. I've been kicking myself to do it for months and recently I got back into it. Tedious, but a lot of fun.
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It's just interesting fun the way I see it. I built quite a few amps since I started coming here a few years ago, and it was just for fun. Of course I actually built a few that I liked! I gave most of them away to relatives and friends, so I'm down to 7 now, with three being factory built. Two Fenders are the next ones to hit the road.
I would still like to build a good single-end, low powered amp. Only built one, and wasn't impressed. Maybe a lousy circuit (?)
I could never build amps as an occupation, just not my thing......